Colon transit time

BMI 19.8-36.0 kg m-2) were studied. All transit variables were unaffected by gender. The older subjects had a slower mean colonic transit time of radiolabeled plastic particles than the young subjects (p < 0.05), while BMI affected the gastric emptying of fiber but not other gastrointestinal variables [22]. In a more recent study, comparison was made between cohorts of young and elderly males, but no age-related effect could be determined [23]. 

Tab. 23.2. Colonic transit times (h) of single unit dosage forms [37],...

Bouchoucha et al. characterized colonic transit time in 30 healthy subjects and in 43 patients with inflammatory bowel disease using X-ray opaque markers. The response to food was different in the two populations in controls, the cecum and ascending colon emptied and filled the distal bowel, whereas in the patients only the splenic flexure and left transverse colon emptied. Movement through both the right and left colon in patients was observed to be much slower than in controls, both before and after a meal [55]. 

Rao et al. [140] described a study using a commercial pH sensitive radio-telemetry capsule (RTC) to evaluate small bowel and colonic transit time in athletes with gastrointestinal symptoms. The RTC (type 7006 Remote Control Systems, London, UK) consists of a glass electrode with an integral reference cap and battery. RF transmissions from the capsule are detected by a solid-state receiver worn on the belt of the patient. The recorder samples the pH from the capsule at 6 second intervals for a period of 24 hours. They used pH changes as an indication of the pH capsule s movement. A sharp rise in pH from around pH 2 to pH 6 indicates that the capsule has moved into the duodenum from the stomach. Then the pH progressively rises to a plateau around pH 8, which indicates that the capsule has moved into the terminal ileum. Another commercially available wireless pH sensor (Bravo) from Medtronic Inc. has been used to measure esophageal pH for a period of 48 hours and it will be discussed later. 

K.A. Rao, E. Yazaki, D. F. Evans and R. Carbon, Objective evaluation of small bowel and colonic transit time using pH telemetry in athletes with gastrointestinal symptoms. J. Sports Med. 38, 482-487... 

Colonic transit time is only slightly affected by food, but is redueed under stress. Studies have shown that drugs, which act on the parasympathetie or sympathetie nervous system, affeet the propulsive motor aetivity, thereby influeneing the eolonie transit time [12]. Although not significantly affected by most diseases [13], the transit time is shorter in patients who complain of diarrhea and longer in patients with eonsti-pation. 

As previously noted, opioids have significant constipating effects (see Chapter 31). They increase colonic phasic segmenting activity through inhibition of presynaptic cholinergic nerves in the submucosal and myenteric plexuses and lead to increased colonic transit time and fecal water absorption. They also decrease mass colonic movements and the gastrocolic reflex. Although all opioids have antidiarrheal effects, central nervous system effects and potential for addiction limit the usefulness of most. 

HT3 receptors in the gastrointestinal tract activate visceral afferent pain sensation via extrinsic sensory neurons from the gut to the spinal cord and central nervous system. Inhibition of afferent gastrointestinal 5-HT3 receptors may inhibit unpleasant visceral afferent sensation, including nausea, bloating, and pain. Blockade of central 5-HT3 receptors also reduces the central response to visceral afferent stimulation. In addition, 5-HT3-receptor blockade on the terminals of enteric cholinergic neurons inhibits colonic motility, especially in the left colon, increasing total colonic transit time. 

Capsule recovery occurred on average at 23.86 h post-dose for Regimen B, at 34.23 h post-dose for Regimen C and at 30.59 h post-dose for Regimen D. This resulted in colonic transit times of 18.52 h for Regimen B, 25.11 h for Regimen C and 24.53 h for Regimen D. 

Very few data are available on gastrointestinal pH in children. In 12 healthy subjects aged 8-14 years, the mean gastric pH was 1.5 and duodenal pH was 6.4, but this gradually rose in the small intestine reaching a peak value of 7.4 in the distal ileum.The pH dropped to 5.9 as the pH radiotelemetry capsule entered the caecum but increased to 6.5 in the rectum. The median gastric residence time of the telemetry capsule was 1.1 h, small intestinal transit time was 7.5 h, and colonic transit time was 17.2 h. 

There have been several reviews of the pharmacology and use of alosetron (1-5). In patients with irritable bowel syndrome, alosetron increases colonic transit time and colonic compliance. It produces significant improvement in abdominal pain, stool consistency, and frequency and... 

C Calcium and iron supplementation are common causes of constipation. Polycarbophil, a bulk-forming laxative, exerts its therapeutic effect by increasing the mass and water content of stool and by speeding transit time in the colon. Cascara sagrada and sennosides are cathartics, which speed colonic transit time and alter water and electrolyte transport across the colonic mucosa. Sodium biphosphonate is a saline cathartic, which increases intestinal peristalsis by osmotic properties. Docusate sodium is a stool... 

Approximately 90%-95% of cases of childhood constipation are likely to represent functional constipation. Rectal distention is present in nearly all cases and failure of the external anal sphincter and/or pub-orectalis muscle to relax during defaecation attempts has been found in the majority of these children. Whilst delayed colonic transit time may be part of the problem, pelvic floor dysfunction seems to be the dominating factor (Loening-Baucke 1993). 

In 15 male volunteers, naloxone-3-glucu-ronide 0.16 mg/kg reversed constipation due to morphine without altering its analgesic effects colonic transit time was delayed with the addition of naloxone-3-glucuronide [128. ... 

Netzer P, Sendensky A, Wissmeyer MP, Baumeler S, Batista C, Scheurer U, Krause T, Reber P, Brenneisen R. The effect of naloxone-3-glucuronide on colonic transit time in healthy men after acute morphine administration a... 

Increased fiber intake and the consumption of fruits and vegetables are well-known chemopreventive dietary strategies against colon carcinogenesis. It is reported that fiber intake reduces colonic transit time and increases the production of short chain fatty acids such as butyric acid. The latter is produced in the mammalian colon in mM concentrations as a by-product of anaerobic bacterial fermentation of dietary fiber. Butyric acid has been recognized as one candidates chemopreventive active against colon carcinogenesis because it induces apoptosis and differentiation in colon cancer cell lines. 

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